Varro claims that he believes that "God" is the soul of the world--that is, creation is God's body and He is its animating force. In that sense, the whole world is God. (Chapter 6)
If that is indeed the case, what grounds do we have for discriminating between two different gods? How can we articulate the difference between Janus and Terminus? Why do we have festivals to each of these gods, and give them different months? (January and February respectively.)
For that matter, the pagans cannot even really agree on Janus himself--is he two-faced or four-faced? How can he guard all entrances and doors when he does not even have a set number of faces? Instead, let us turn to Him who says 'I am the door.'